With the proliferation of wireless communication systems, compatible handheld communication devices are becoming more prevalent, as well as advanced. Whereas in the past such handheld communication devices were typically limited to either voice transmission (cell phones) or text transmission (pagers and PDAs), today's consumer often demands a multifunctional device capable of performing both types of transmissions, including even sending and receiving e-mail. Furthermore, these higher-performance devices can also be capable of sending and receiving other types of data including that which allows the viewing and use of Internet websites. These higher level functionalities necessarily require greater user interaction with the devices through included user interfaces (UIs) which may have originally been designed to accommodate making and receiving telephone calls and sending messages over a related Short Messaging Service (SMS). As might be expected, suppliers of such mobile communication devices and the related service providers are anxious to meet these customer requirements, but the demands of these more advanced functionalities have in many circumstances rendered the traditional user interfaces unsatisfactory, a situation that has caused designers to have to improve the UIs through which users input information and control these sophisticated operations.
Keyboards are used on many handheld devices, including telephones and mobile communication devices. The size of keyboards has been reduced over the years, as newer, smaller devices have become popular. Cell phones, for example, are now sized to fit in one's pocket or the palm of the hand. As the size of the devices has decreased, the more important it has become to utilize the entire keyboard surface as efficiently as possible.
Many keyboards on mobile devices have an input device for navigation through the graphical user interface. These interfaces include such devices as trackballs and rotating wheels which can be used to effect movement of a cursor or pointer, or to scroll up, down and about a displayed page. These navigation devices often occupy a relatively large amount of space on the incorporating mobile device. Because the navigation device is frequently used and often requires fine control, a lower end size limitation will normally be observed by device designers. To accommodate such larger, more convenient navigation devices on the housing of the mobile device, the amount of space that is available for the keys of the keyboard is correspondingly reduced if the keyboard and navigational device are proximately located to one another.
As the proliferation of wireless handheld communication devices continue, users increasingly send and receive emails on their handheld communication devices. The screen of a typical handheld device is very small in comparison to a standard desktop computer station. In sending and receiving email messages, many users implement filters on their desktops in order to prioritize or otherwise sort through their incoming and/or outgoing messages. However, users may not implement filters on the messages sent to and from the handheld communication device email software. Thus, an easy way to distinguish the intended recipient or sender of an email message is needed.